脚手架安装后，asp.net mvc核心索引页上显示外键的问题

我最近将一些Asp.net mvc5应用程序升级到了asp.net mvc core3。我在索引页上显示外键时遇到问题。它们在mvc 5中显示正常，但不在mvc core中显示。我将包括相关的代码文件。这三个外键分别是“部门”，“项目”和“请求类型”。任何想法都会有所帮助。

谢谢。

SolicitationsController.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.Rendering;
using Microsoft.EntityFrameworkCore;
using TOGSolicitations.Models;

namespace TOGSolicitations.Controllers
{
    public class SolicitationsController : Controller
    {
        private readonly TOGProjectsContext _context;

        public SolicitationsController(TOGProjectsContext context)
        {
            _context = context;
        }

        // GET: Solicitations
        public async Task<IActionResult> Index()
        {
            Microsoft.EntityFrameworkCore.Query.IIncludableQueryable<Solicitations, SolicitationType> tOGProjectsContext = _context.Solicitations.Include(s => s.Department).Include(s => s.Project).Include(s => s.SolicitationType);
            return View(await tOGProjectsContext.ToListAsync());
        }

        // add Search ablity on the Index Page
        [HttpGet]
        public async Task<IActionResult> Index(String Solicitationsearch)
        {
            ViewData["GetSolicitationDetails"] = Solicitationsearch;

            var solicitationquery = from x in _context.Solicitations select x;
            if (!String.IsNullOrEmpty(Solicitationsearch))
            {
                solicitationquery = solicitationquery.Where(x => x.SolicitationNumber.Contains(Solicitationsearch) || x.SolicitationDescription.Contains(Solicitationsearch));
            }
            return View(await solicitationquery.AsNoTracking().ToListAsync());
        }

        // GET: Solicitations/Details/5
        public async Task<IActionResult> Details(short? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var solicitations = await _context.Solicitations
                .Include(s => s.Department)
                .Include(s => s.Project)
                .Include(s => s.SolicitationType)
                .FirstOrDefaultAsync(m => m.SolicitationId == id);
            if (solicitations == null)
            {
                return NotFound();
            }

            return View(solicitations);
        }

        // GET: Solicitations/Create
        public IActionResult Create()
        {
            ViewData["DepartmentId"] = new SelectList(_context.Departments, "DepartmentId", "DepartmentName");
            ViewData["ProjectId"] = new SelectList(_context.Projects, "ProjectId", "ProjectDescription");
            ViewData["SolicitationTypeId"] = new SelectList(_context.SolicitationType, "SolicitationTypeId", "SolicitationTypeDescription");
            return View();
        }

        // POST: Solicitations/Create
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Create([Bind("SolicitationId,FiscalYear,SolicitationTypeId,SolicitationNumber,DepartmentId,SolicitationDescription,BidDate,VendorSelected,SolicitationPrice,PurchaseOrderNumber,EngineeringProjectNumber,ProjectId")] Solicitations solicitations)
        {
            if (ModelState.IsValid)
            {
                _context.Add(solicitations);
                await _context.SaveChangesAsync();
                return RedirectToAction(nameof(Index));
            }
            ViewData["DepartmentId"] = new SelectList(_context.Departments, "DepartmentId", "DepartmentName", solicitations.DepartmentId);
            ViewData["ProjectId"] = new SelectList(_context.Projects, "ProjectId", "ProjectDescription", solicitations.ProjectId);
            ViewData["SolicitationTypeId"] = new SelectList(_context.SolicitationType, "SolicitationTypeId", "SolicitationTypeDescription", solicitations.SolicitationTypeId);
            return View(solicitations);
        }

        // GET: Solicitations/Edit/5
        public async Task<IActionResult> Edit(short? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var solicitations = await _context.Solicitations.FindAsync(id);
            if (solicitations == null)
            {
                return NotFound();
            }
            ViewData["DepartmentId"] = new SelectList(_context.Departments, "DepartmentId", "DepartmentName", solicitations.DepartmentId);
            ViewData["ProjectId"] = new SelectList(_context.Projects, "ProjectId", "ProjectDescription", solicitations.ProjectId);
            ViewData["SolicitationTypeId"] = new SelectList(_context.SolicitationType, "SolicitationTypeId", "SolicitationTypeDescription", solicitations.SolicitationTypeId);
            return View(solicitations);
        }

        // POST: Solicitations/Edit/5
        // To protect from overposting attacks, please enable the specific properties you want to bind to, for 
        // more details see http://go.microsoft.com/fwlink/?LinkId=317598.
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Edit(short id, [Bind("SolicitationId,FiscalYear,SolicitationTypeId,SolicitationNumber,DepartmentId,SolicitationDescription,BidDate,VendorSelected,SolicitationPrice,PurchaseOrderNumber,EngineeringProjectNumber,ProjectId")] Solicitations solicitations)
        {
            if (id != solicitations.SolicitationId)
            {
                return NotFound();
            }

            if (ModelState.IsValid)
            {
                try
                {
                    _context.Update(solicitations);
                    await _context.SaveChangesAsync();
                }
                catch (DbUpdateConcurrencyException)
                {
                    if (!SolicitationsExists(solicitations.SolicitationId))
                    {
                        return NotFound();
                    }
                    else
                    {
                        throw;
                    }
                }
                return RedirectToAction(nameof(Index));
            }
            ViewData["DepartmentId"] = new SelectList(_context.Departments, "DepartmentId", "DepartmentName", solicitations.DepartmentId);
            ViewData["ProjectId"] = new SelectList(_context.Projects, "ProjectId", "ProjectDescription", solicitations.ProjectId);
            ViewData["SolicitationTypeId"] = new SelectList(_context.SolicitationType, "SolicitationTypeId", "SolicitationTypeDescription", solicitations.SolicitationTypeId);
            return View(solicitations);
        }

        // GET: Solicitations/Delete/5
        public async Task<IActionResult> Delete(short? id)
        {
            if (id == null)
            {
                return NotFound();
            }

            var solicitations = await _context.Solicitations
                .Include(s => s.Department)
                .Include(s => s.Project)
                .Include(s => s.SolicitationType)
                .FirstOrDefaultAsync(m => m.SolicitationId == id);
            if (solicitations == null)
            {
                return NotFound();
            }

            return View(solicitations);
        }

        // POST: Solicitations/Delete/5
        [HttpPost, ActionName("Delete")]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> DeleteConfirmed(short id)
        {
            var solicitations = await _context.Solicitations.FindAsync(id);
            _context.Solicitations.Remove(solicitations);
            await _context.SaveChangesAsync();
            return RedirectToAction(nameof(Index));
        }

        private bool SolicitationsExists(short id)
        {
            return _context.Solicitations.Any(e => e.SolicitationId == id);
        }
    }
}

征集

using System;
using System.Collections.Generic;
using System.ComponentModel.DataAnnotations;
using System.ComponentModel;

namespace TOGSolicitations.Models
{
    public partial class Solicitations
    {
        public short SolicitationId { get; set; }
        [DisplayName("Fiscal Year")]
        public short FiscalYear { get; set; }
        [DisplayName("Solicitation Type")]
        public short SolicitationTypeId { get; set; }
        [DisplayName("Solicitation Number")]
        [Required, StringLength(25)]
        public string SolicitationNumber { get; set; }
        [DisplayName("Department")]

        public short DepartmentId { get; set; }
        [DisplayName("Solicitation Description")]
        [Required, StringLength(80)]
        [RegularExpression(@"(([A-za-z0-9\s\-]+))$")]
        public string SolicitationDescription { get; set; }
        [DisplayName("Bid Date")]
        [DisplayFormat(ApplyFormatInEditMode = true, DataFormatString = "{0:MM/dd/yyyy}")]
        public DateTime? BidDate { get; set; }
        [DisplayName("Vendor Selected")]
        [StringLength(80)]
        public string VendorSelected { get; set; }
        [DisplayName("Solicitation Price")]
        [RegularExpression(@"(([A-za-z0-9\s\-\.]+))$")]
        public decimal? SolicitationPrice { get; set; }
        [DisplayName("Purchase Order Number")]

        public string PurchaseOrderNumber { get; set; }
        [DisplayName("Enginnering Project Number")]
        [StringLength(10)]
        [RegularExpression(@"(([A-za-z0-9\s\-]+))$")]
        public string EngineeringProjectNumber { get; set; }
        [DisplayName("Project Description")]

        public int? ProjectId { get; set; }

        public virtual Departments Department { get; set; }
        public virtual Projects Project { get; set; }
        public virtual SolicitationType SolicitationType { get; set; }
    }
}

征集索引.cshtml

@model IEnumerable<TOGSolicitations.Models.Solicitations>

@{
    ViewData["Title"] = "Solicitations";
    Layout = "~/Views/Shared/_Layout.cshtml";
}

    <div style="=font-family:Arial">
        <h1>Solicitations</h1>

        <p>
            <a asp-action="Create">Create New</a>
        </p>

        <form method="get" asp-action="Index">
            <p>
                <input type="search" placeholder="Enter Solicitation Number or Solicitation Description ..." value="@ViewData["GetSolicitationDetails"]" name="Solicitationsearch" style="width:500px;" />
                <input type="submit" value="Search" class="btn btn-primary" />
                <a asp-action="Index">Get All Solicitations</a>
            </p>
        </form>

        <table class="table" border="1">
            <thead>
                <tr>
                    <th>
                        @Html.DisplayNameFor(model => model.FiscalYear)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.SolicitationNumber)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.SolicitationDescription)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.BidDate)
                    </th>

                    <th>
                        @Html.DisplayNameFor(model => model.EngineeringProjectNumber)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.Department)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.Project)
                    </th>
                    <th>
                        @Html.DisplayNameFor(model => model.SolicitationType)
                    </th>

                    <th width="100">Action </th>
                </tr>
            </thead>
            <tbody>
                @foreach (var item in Model)
                {
                    <tr>
                        <td>
                            @Html.DisplayFor(modelItem => item.FiscalYear)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.SolicitationNumber)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.SolicitationDescription)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.BidDate)
                        </td>

                        <td>
                            @Html.DisplayFor(modelItem => item.EngineeringProjectNumber)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.Department.DepartmentName)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.Project.ProjectDescription)
                        </td>
                        <td>
                            @Html.DisplayFor(modelItem => item.SolicitationType.SolicitationTypeDescription)
                        </td>
                        <td>
                            <a asp-action="Edit" asp-route-id="@item.SolicitationId">Edit</a> |
                            <a asp-action="Details" asp-route-id="@item.SolicitationId">Details</a> |
                            <a asp-action="Delete" asp-route-id="@item.SolicitationId">Delete</a>
                        </td>
                    </tr>
                }
            </tbody>
        </table>
    </div>